While there are many systems for production of bone from cell-cell interactions between mesenchymal cells and uroepithelium or HeLa cells or amnion or transformed fibroblasts, only one system produces bone from interaction of mesenchymal cells with a chemically defined inductive substratum. This system consists of interaction of mesenchymal cells or young fibroblasts with either dentin or bone or osteosarcoma matrix. In tissue culture, the product is cartilage while in vivo, bone and bone marrow. The proposed research on the morphogenetic response to bone matrix has experimental and clinical objectives. The experimental objective is to isolate and characterize the bone morphogenetic protein (BMP) in dentin and bone matrix. BMP is bioassayed by implantation of lyophilized samples of pore size as small as 0.25 microns in allogeneic rabbits, rats and mice. Soluble BMP is to be characterized by chemical analyses, gel filtration, gel electrophoresis, immunophoresis, column chromatography, amino acid analyses, and amino acid sequenation. The clinical objective of the research is to prepare osteoinductive dentin and bone alloimplants for patients with jaw bone and long bone defects derived from tumors, infections, injuries, and congenital malformations. Knowledge of the physiology of the inductive matrix is applied in the preparation of a chemosterilized, autolysed antigen extracted, allogeneic (AAA) bone graft. The experimental program is to characterize the biochemical components of dentin, bone and osterosarcomas responsible for the osteoinductive response in adult rabbits, rats, and mice.